Callus: The mass of parenchyma cells that develops from and around wounded plant tissues in order to diminish evaporation from the wound and initiate healing. In grafting it occurs at the junction of a graft union, arriving from living cells of both scion and stock. The production and interlocking of these parenchyma (or callus) cells constitute one of the important steps in the healing process of a successful graft.
Cambium: A thin tissue of the plant located between the bark and the wood. Its cells are meristematic, i.e. they are capable of dividing and forming new cells. For a successful graft union, it is essential that the cambium of the scion be placed in close contact with the cambium of the stock.
Clone: A population of genetically identical cells or individuals. Such a population is obtained by mitotic division or by asexual reproduction.
Distal: The distal end of either the root or the shoot is that furthest from the stem-root junction of the plant and nearest to the tip of the shoot or root. Alt. proximal. See polarity.
Dormant/dormancy (buds): A bud which have stopped its development for a period due to unfavourable environmental conditiones (e.g. a dry or cold season). A dormant bud will sprout as a response to improved growth conditions or a “biological clock” e.g. longer days.
Grafting: The connection of two pieces of living plant tissue in such a manner that they will unite and subsequently grow and develop as one plant.
Grafting wax: Substance applied on the graft union in order to minimise desiccation and exclude water access.
Graft union: The site of the grafted plant where the scion and the root stock are united.
Hedging: Trimming trees and keeping them low in order to overcome or bypass the poor rooting and often poor form of cuttings from old trees. Cuttings from hedged plants tend to maintain their young physiological age.
Hormone: A substance that has a marked effect on a specific plant part and produces this effect when present in very low concentrations, e.g. promotion of root, shoot or flower development. Hormones are produced within the plant but artificial synthesized plant hormones applied to the plant part have the same effect.
Incompatibility (graft incompatibility): Inability of the stock and the scion to form or maintain a union that will result in the desired plant growth.
Node: A point of the stem from which one or more leaves arise. In the mature stem the nodes are usually well separated by internodes which elongate during growth.
Ortet: The original plant from which a clone has been derived.
Orthotropic growth: The situation where the vegetative propagule assumes an upright or normal tree form. Ant. plagiotropic growth.
Periphysis: Variation of growth habit of vegetative propagules due to their origin from different environments, such as shade and sun leaves on an individual tree.
Plagiotropic growth: The situation where the vegetative propagule does not assume a normal tree form but continues to grow like a branch. Ant. orthotropic growth.
Propagule: A plant part such as a bud, tuber, root or shoot, used to propagate an individual vegetatively.
Polarity: The condition that plant parts maintain their spatial orientation when separated from the mother plant. The phenomenon is important in cuttings and grafting. See proximal and distal.
Proximal: The end of either the root or the shoot that is nearest the stem-root junction of the plant. See polarity
Ramet: An individual member of a clone.
Scion: An aerial plant part, often a branchlet, that is grafted onto the root bearing part (stock/root-stock) of another plant.
Stock/root stock: The lower portion of the graft, which develops into the root system of the grafted plant. It may be a seedling, a rooted cutting or a layered plant.
“Take”: The “slang” term for the phenomenon of the successful union of stock and scion and growth of the grafted plant.
Topophysis: The phenomenon that occurs when scions, buddings and rooted cuttings maintain for some time the branchlike growth habit (plagiotropic growth) they had as shoots on the ortet.